1. Field of Invention
The present invention relates to an inkjet printhead chip. More particularly, the present invention relates to an inkjet printhead chip with transistor drivers.
2. Description of Related Art
With the rapid development in the electronic industry, many high-tech products are produced in recent years. In particular, there is a major revolution in the design of printers, from the pin-activated and monochromatic laser printing to color inkjet and color laser printing. The two major methods used by a conventional inkjet printer for producing ink jets are the piezoelectric and thermal bubble techniques. One major aspect of the techniques is to target jets of ink onto a recording medium such as a paper so that words, images, or patterns are formed on the surface of the recording medium. In the piezoelectric jetting technique, the actuator is a piezoelectric material layer. When a voltage is applied to the piezoelectric material, the piezoelectric layer deforms to pressurize the ink within an ink chamber so that a jet of ink is forced out from the ink chamber via an ink nozzle. In the thermal bubble jetting technique, a small quantity of ink is rapidly vaporized by a heater (resistor) to generate a sudden increase of pressure in the ink so that a droplet of ink is squeezed out from an ink chamber via an ink nozzle.
FIG. 1 is a plan view, schematically illustrating a conventional inkjet printhead. Referring to FIG. 1, the conventional inkjet printhead mainly has an inkjet printhead chip 100 with an ink supply slot 102, a chamber layer (also called dry film layer) 104, a heating device (heater) 106 and a nozzle plate 110 with nozzle 108. The ink supply slot 102 has an elongated shape (but can also be in other shapes such as an elliptical or circular shape) and is formed through the entire inkjet printhead chip 100. The heating device 106 and the chamber layer 104 are formed over the inkjet printhead chip 100. The chamber layer 104 usually has a plurality of ink flow channels 112 and an ink chambers 120 (only one of them is shown in FIG. 1). The ink chamber 120 exposes the heating device 106 and communicates with the ink supply slot 102 via the ink flow channels 112 separated optionally by separators 114. The nozzle plate 110 is positioned above the chamber layer 104 and has a plurality of nozzles (only one of them is shown in FIG. 1). The nozzle 108 of the nozzle plate 110 is formed through the entire thickness of the nozzle plate 110, and is positioned above the corresponding heating device 106.
In addition, the drivers and heating devices are integrated onto the inkjet printhead chip in some inkjet cartridges or printers. However, how to reduce the area of the chip while maintaining its performance has been one of the issues considered by the persons skilled in the art.